The present invention was developed in response to a need for increasing the life capability in crossed-field amplifiers used within existing radar systems without sacrificing any of the performance capabilities of the crossed-field amplifiers.
Crossed-field amplifiers have been known for several years. These amplifiers are typically used in electronic systems which require high voltages, such as radar systems. Typically, the cathode in such amplifier is a thermionic-type emitter which operates on the principle of direct heating to boil off electrons. A problem with such thermionic cathodes used in crossed-field amplifiers is their relatively short life capability, generally on the order of about 1000 hours of operation. Failure of the crossed-field amplifier due to the short life span of its thermionic cathode causes the radar system incorporating the crossed-field amplifier to be inoperable.
It is known that improved life capability of crossed-field amplifiers may be achieved by using a non-thermionic emitter cathode. Typically, pure metal, secondary-emitter type cathodes, such as ones made of molybdenum, platinum, or nickel may be used. Such secondary emission type cathodes operate on the principle of bombarding the metal with electrons to drive off additional electrons which then spin toward an anode.
However, existing secondary emission type cathodes fall short of meeting the performance requirements of existing radar systems, particularly in the area of current mode boundaries.